DE517231C - Film indexing device for series image measuring chambers - Google Patents

Description

GERMAN EMPIRE

ISSUED Ape FEBRUARY 2, 1931.

REICH PATENT OFFICE

PATENT LETTERING

Ji (I517.231 CLASS 57a GROUP

Photogrammetry G. m. B. H. in Munich

Film advancing device for serial image measuring chambers Patented in the German Empire on October 9, 1928

On film advance devices for continuous picture recordings From the aircraft, the highest demands must be made in terms of operational safety and accuracy will. The friction rollers often used to dimension the switching path allow as experience teaches, the possibility of that, especially according to the at greater altitudes the film against any fluctuations in temperature and humidity , the friction rollers slips, so that the length of the actually transported film piece is smaller than the unwound roller circumference. Two consecutive recordings then move closer together than intended by the amount of the slip, they partially overlap and thereby make the elaboration impossible or endanger it to a high degree. Around

Various devices are used to eliminate a risk became known, which by a perforation of the film tape and by organs that engage in this perforation, a slip of the film tape against

try to prevent the rollers providing or measuring the transport. at However, some of these devices use the perforation to remove the film tape on the organs engaging the perforation or reverse force in the direction of the To transfer the transport route. The perforation is thereby stressed in the most unfavorable way, namely under pressure on the reveal and thereby exposed to the risk of destruction. A destruction of the perforation tearing or flanging the edges then easily causes disruptions in the film transport.

Some other devices have become known which add to this disadvantage seek to eliminate that marks attached to the film tape (incisions, perforations) a sensing element is actuated, which drives the transport after an image length has elapsed locks by falling in a latch.

The present invention relates to a device of the latter type, but which In contrast to already known similar devices, it is designed in such a way that the economy required for series image measuring chambers of film material and a high level of operational reliability. According to the invention the film tape to be used is placed in each gap between two before being introduced into the chamber Image areas and only there with a perforation, into which when transporting the film introduced into the chamber after one image length has elapsed perpendicular to the surface a latch occurs on the film tape, which - without applying any force to the film tape itself to transfer - by this falling into the aforementioned perforation the drive of the Film tape blocks so that the drive member no longer transmit any force to the film can.

The illustration shows a
form of invention.

Execution

By means of a crank α, the take-up roller e provided with a toothed ring d is driven by the toothed wheel wedged onto the crankshaft b. This pulls the film tape placed around it /, which comes from the supply roll g and runs over two guide rollers Ji , in front of the opening that limits the image format? past. The film tape has individual holes Ji ₁ , Jt. _A k _s> fe ₄ , which by the amount of the distance

ίο two consecutive recordings are spaced apart. These holes lie in the space between two consecutive images. A lever I with its one end designed as a nose m is always pressed lightly against the film tape by means of a spring η and falls into the same when a hole in the perforation slides away from under it. The crank α and thus the film transport as such are blocked by a ratchet tooth 0 attached to the other end of the lever, which at this moment engages the gear wheel p firmly connected to the transport gear c. Now the recording takes place by pressing down the release lever q. This pivots the lever I by means of a driver r and thereby causes the ratchet tooth 0 to release the gear wheel p and the lug m to release the hole k "again. Simultaneously with the turning of the lever / the thumb j is pulled to the right by the spring t , so that its upper end presses against the gear c and thereby prevents the nose in and the ratchet 0 from immediately coming into engagement again, when the shutter release lever q returns to its original position. If the film is now switched on by turning the crank α, which has now become free again, the tip of the thumb s is carried along to the left by the teeth of the gear c; the lever I is from the spring ?! tightened so far that the nose m grinds on the film tape. If the film has covered a path corresponding to the distance between the film, the hole Ji comes to lie under the nose; the lever / locks the transport again, whereupon the process is repeated.

Instead of blocking the transport of the film tape, as in the embodiment described happens, a clutch can be switched between the crank and the take-up roll, which after Advancement is disengaged by one frame length, so that the crank α runs idle until the Exposure is done. The re-engagement of the transport device can also by Coupling with other mechanical organs of the exposure process (cocking the shutter, Pressing the film or releasing the pressure and the like) or can be brought about by a separate move.

Claims (1)

Claim: Film tracking device for serial image measuring chambers, especially for taking pictures from an aircraft, in which the drive of the film tape is blocked or decoupled by a feeler lever sliding on the film tape after each image length has elapsed, characterized in that the film tape has holes in every space between two successive images ( A ₁ k ₂ , k ₅ ) into which a feeler lever (I, m) falls perpendicular to the plane of the film tape after each image length has elapsed. 1 sheet of drawings